BuddyPress Auto Activate Auto Login plugin makes it easy for new users to join  BuddyPress site. It removes the email activation requirement for new accounts and automatically activates the user account and makes them automatically logged in when they register on a BuddyPress based site.

The goal of this plugin is to allow better interaction and make the BuddyPress registration a pleasant experience. This plugin helps webmasters to get more signups with ease and expand their network.  Sometimes, if you have issues with BuddyPress activation email, this plugin can help in that too, by removing the email activation requirement.

Here is a list of things it does:-

Auto activate  user account instantly on sign up

Stop the activation mail sent to user( there is no more activation mail  required, as the accounts are automatically activated )

After, activating the user account, this plugin logs them in automatically and redirects the user to their profile.

So basically, It provides a seamless experience for your users. Once your user clicks “Complete Signup”(whatever you call it on your registration page), their account will be automatically activated, they will be logged in and redirected to their new profile.  All they see is your signup page and the next page is their own profile.

This plugin works perfectly for Multisite as well as standard WordPress installation. On Multisite, It will handle both type of registration:-

User registers for a user name only(i.e no blog at signup)

User registers for username and blog both

This plugin works for WordPress as well as WordPress Multisite install of BuddyPress